Archive of ‘Math 7’ category

Finishing Our Work

My teacher is Mr. Fedley and I’m in 7A.

This year, we learned about:

Screen Shot 2014-06-10 at 10.06.49 AM

 

The first unit was Sets & Logic. We learned about equations using sets. We learned about how to use “()” too. It was sometimes confusing. The second unit was about the pythagoreas theorem. However, I knew the pythagoreas theorem so it wasn’t that hard. The last unit for the second semester which is statistics isn’t hard but it is very tiresome.

For the sets unit, we had an assessment with icecreams. The document looked like this: Screen Shot 2014-06-10 at 10.20.18 AM When I was doing this, I wanted to eat ice cream XD! For the pythagoreas theorem unit, our assessment was about triangles.

I enjoyed learning about percentages and ratios because it was quite easy compared to the other units.

The most challenging thing was the exam. Since the exam is an important test and it affects the grade, I needed to try my best and the questions were quite hard.

Next year, I want to focus on my skills and try difficult problems and units.

Statistics

Data 1:

Q: Howmany instruments can you play? A: 2,2,1,1,0,4,0,4,3,0,5,3,1,0,1,1,2,2,3,3

The range is 5

The mean is 1.9

The median is 2

The mode is 1

I collected the data by asking all the people in my class and also chatted 3 people of my friends. The question were supposed to be answered in numbers so it was easy.

I made the data into a pie chart so it is quite easy to see the amount of each number:

Screen Shot 2014-05-23 at 2.59.01 PM

 

I found out the range by subtracting the smallest number to the biggest number. In my data, the biggest number was 5 and the smalles number was 0. Then it will be 5-0 which is 5.

I found out the mean by adding all the numbers and dividing it by the amount of data I have. In my case, the total of all the number was 38 and I surveyed 20 people so it was 38/20 which became 1.9.

I found out the median by sorting out all the numbers by order. It became like this: Screen Shot 2014-05-23 at 3.02.15 PMThen, I crossed out the numbers from both sides one at a time and found the middle number. Since, I had 20 people, it is an even number. Even number has 2 middle numbers so you add the 2 numbers and divide it by 2. My middle number was 2 and 2 so it makes 4 and I divided 4 by 2 and it became 2.

I found out the mode using the numbers in order (Picture in the median part) and I counted each number and there was 4 zeros, 5 ones, 4 twos, 4 threes, 2 fours and 1 five. Which makes 1 the mode since there are the more ones than any other numbers.

My result mean that as an average, a person can play 2 instruments. However, different people can play different amount of instruments!

Ratios & Algebra

We’re gonna have an exam next week and it is on Ratios and Algebras.

Ratios are something that we compare more than 2 numbers using ‘:’. For example, 1:2. Algebra is when we use alphabets to find out problems and equations. The alphabets represents numbers and quantities.

Example questions:

(Ratios)

1. There are 5 boys and 15 girls in a class. What is the ratio of boys to girls? If possible simplify the ratio.

A. 5:15=1:3. The reason why we can simplify the ratio 5:15 to 1:3 is because we can divide both 5 and 15 by 5 so if we divide both numbers by 5, it will become 1 and 3.

2. There are 2 erasers, 4 pencils and 6 pens in a pencil case. What is the ratio of pencils to pens to eraser. Simplify if possible.

A. 4:6:2=2:3:1. In this case the order needs to be pencils then pens then eraser because the order of the things in the sentence is in this order using ‘to’.

(Algebra)

1. Mr. Fedley and Ms. Winslade likes coke. Mr. Fedley buys 7 more  bottles than Ms. Winslade does everyday. Ms. Winslade buys 2 bottles per day. How many bottles does Mr. Fedley buy per day? Represent Mr. Fedley as x.

A. x=7+2; x=9; which means Mr. Fedley buys 9 bottles per day.

2. Satono and Ayaka brings snacks to school everyday. Ayaka always brings 2 more snacks than Satono. Satono brings 2 snacks everyday. How many snacks does Ayaka bring? Represent Ayaka as a.

A. a=2+2; a=4. Ayaka brings 4 snacks everyday.

I enjoyed doing algebra the most because I like working out the equations because it is fun thinking of equations. Also, it is easy to notice if the equation is wrong because you can easily notice if the answer will be wrong or not.

I didn’t think any of the topics were challenging however, I don’t really like ratios.

To  improve my knowledge for both topics, I can work on problems of the two topics more by searching it on the internet. Also I can look at videos that are related to the topics but is a bit more challenging.

My Reflection of Semester 1 Math

(I can’t really remember all the things we did so I will reflect what we did from the posts on  my blog)

First, we learned about venn diagrams. I really liked making our original venn diagrams because we were allowed to do our venn diagrams mostly on any topic. Some people did crazy topics and some people just did their favorite artists, games, subject etc… Also in this unit, we made a video about our original story using venn diagrams.

Second thing we learned is about possibility. For this unit, we went to the auditorium and played games the 8th graders thought of. We needed to think of the possibility to win the game because the most class that had the most tokens won the game. The class that won was 7B.

The third thing we learned about was measuring distances. During this unit, we learned the pythagorean theorem. For the final task, we estimated the distance from marine tower and some places that is quite famous in Japan. Then, went to marine tower and checked the correct answer and we re-estimated the distances for the ones which didn’t have answers.

Finally, we learned about percentages. The first thing we did in this unit was we needed to write a blog post about percentages. The most hardest thing that was when writing the blog post was that I couldn’t write what I was thinking about because some ideas were quite hard to write in words.

The most thing I enjoyed in Semester 1 was making our original venn diagrams. I liked it because my topic, which was the types of games, was hard to find the common thing between each thing. Also, the other one I made which is about my classmates’ personalities, I had 3 sections. Athletic, Artistic and Intelligent. I didn’t know who was intelligent because some people weren’t in my class in the past so I didn’t really know if they were intelligent or not. Even though I didn’t know, I picked the people who were intelligent or not by if they looked intelligent or not.

I didn’t enjoy making the venn diagram video because I didn’t know what to say in the video. When I mean I didn’t know what to say, I didn’t know how to explain some slides and also I couldn’t really speak how venn diagrams work.

The work I am most proud of is the blog post about estimating the distance from Marine Tower. I am proud of this because I think I had detail on my blog post and added the links to the places if there is one.

For this semester, I want to improve to write details and read the questions more carefully so I can get good grades. Also I want to make sure that I go back my work before I give it to the teacher so I can find places that I can improve more on!

 

 

Forced To Write A Percentage Blog Post :P

A percentage is something you learn in math class. You use a sign called “Percentage Sign” which is ‘%’. It is out of 100. You can see how much of something is in something. For example, 50% is half of something. This means 50 % of 8 is 4 becasue 100/50=2 and 8×1/2 is 4. 25% os a quarter of something because 100 divide by 25 is 4. If you want to find out 25% of 40, you need to 40/4 or 40×25/100. It will equal 10 in both ways. Now, I will tell you how to find out the percentage of something. For example, there are 50 marbles in a bag. There are 5 red marbles. What is the percentage of picking a red marble from the bag?  To work out- 

First of all, you need to make the numerator what you want to find out, and the denominator the total amount. Then you divide it. In this case, the numerator was 5 and the denominator was 50. Then the answer was 1/10 (0.1). Then you times the answer by 100. Finally, the answer will come out. In this example it was 0.1×100 which equals 10. Also, you can divide the denominator with the numerator first. Which is 50/5=10. Then you can just divide 10 by 100 and then that will equal the percentage which is 10%.

Another example is there are 48 markers in the jar. There are 8 green markers in the jar. What is the percentage of picking a green marker out of the jar? To work out- 

In this case, the numerator is 8 and the denominator is 48 because we want to know the percentage of taking out 8 green markers from a jar with 48 markers. Then, you divide 8 from 48. This equals 1/6 (0.16666(0.17)). Then you multiply 100 to 0.16666. It will then equal 16.666. If you want to round it up to the second power point, it will be 16.67 because 6 is bigger than 5 so you make the digit on the second power 1 higher. If you want to make it the first power, it will be 16.7 because same as the second power, 6 is higher than 5. If you want to round it up to a whole number, it will be 17% because then, .7 or .67 or .666 is bigger than .500.

The most important thing you need to be careful is that to not make the denominator and numerator opposite because if you make it opposite, you can’t find your percentage. However, if you made that mistake, you still can see if you made it the opposite or not. E.g.:

 If you want to find out the percentage of the shaded part, of this, you can see it’s not 100% because 100% is everything and in this one, only 1/3 of the shape is shaded.

 

Math: Estimating Distances

Before we went to Marine Tower, we estimated the distance from Marine Tower to:

When we got to marine tower, there were answers for the distance of Marine Tower to:

  • Mount Fuji
  • Tokyo Skytree

When we found out the answers, we found out the difference between our estimate and the correct answers.

My prediction was:

  • Mount Fuji- 2000km
  • Motomachi Arch- 1km
  • top of Tokyo Skytree- 110km
  • top of Yokohama Ferris wheel- 12km
  • Yokohama Stadium- 10km
  • YCAC- 20km
  • YIS- 2km
  • The horizon- 475km

The correct answer was:

  • Mount fuji- 84km
  • Tokyo Skytree- 32km
  • Yokohama Stadium- 900m

The other distances I got that wasn’t on the list was:

I re-estimated the places that weren’t on the list. My new estimate was:

  • Motomachi Arch- 300m
  • YIS- 550m
  • YCAC- 3.5km
  • The horizon- 40km
  • top of Yokohama Ferris wheel- 2km

The difference of my estimate and the actual distance was very different because I didn’t know how long was 1km, so I thought Motomachi to Marine Tower was 1km but it was actually 300m (with my re-estimated distance). I thought that Mt. Fuji to Marine Tower but 2000km bue it was actually 84km. You can see that the length of 1km I thought was a very short distance.

I thought the estimated distance of Marine Tower to YIS, The horizon, YCAC and the top of the ferris wheel changed a lot comapred to the first estimate and the second estimate because When I got to the top of the Marine Tower, I got the answer for the Forerign cemetery, and the Foreign cemetery is quite close to YIS. Also, when I went to the top of the Marine Tower, my idea for the distance for “1km” changed since 1.2km was quite long when I saw the red brick ware house from the observation deck.

Math games Activity

On October 15th, we went to the auditorium to do the 8th graders’ casino games for period 1 and 2. First we had 15 tokens to play the game. Our purpose was to do the games and see which class had the most tokens left after the games. It will be counted by the average number for the tokens each person has. There were 20~25 games. Each games had different rules, and the amount of tokens you pay and you get were all different. Some were easy to win, some were hard to win.

↑This is how the auditorium looked. As you can see, it was very crowded because there were lots of games and there were two grades. 6th grade and 7th grade.

↑This game was quite crowded because the possibility of winning was about 75%. The rule for this game was you pick a card from the pile and if you get a red card, you were able to roll the dice and there was a list for how many tokens you get to get with the number of dice. The list was:

5,6,7,8,9- 1 token

4,10- 2 tokens

3,11- 3 tokens

2,12- 4 tokens.

Most of the games used cards and dices, but there were some games that didn’t.

Eg.

←This game used marbles

←This game used candies

←This game used pictures of toy ducks

 

There were rules on each table so each person can read the rules and decide if they want to play the game or not before they spend their tokens.

The games I played was the one you pick a card from a pile and pick the red card and roll the dice; picking the red marble; picking the red candy.

I thought some games were fair and some were not. The one which you pick the red car and roll the dice was fair because the possibility of getting at least 1 token was quite high. However picking the red marble one and picking the red candy wasn’t that fair because I think there were only 1 or 2 red marbles in the bag, and only about 3 or 4 red candies in the box. I made a profit for the red card one and the candy one. I did the red card one a few times and I mostly made a profit because the possibility of making a profit is quite high. When I did the candy game I think it was a miracle because when I saw the other people doing the game, most of the people lost. Also as I said above, there were more yellow, blue, green etc… candies more than the red candies. I did the marble one twice but I lost both times. I think I lost this because like the candy game, there were more blue marbles than the red marbles.

I learnt that when you spend your tokens, you need to check the rules and find out the ratio of making a profit and loosing otherwise, you will throw away all of your tokens.

VENN DIAGRAM with NUMBERS

This means there are 4 athletic people, 2 artistic people, 2 intelligent people, 5 athletic & intelligent people, 1 artistic and intelligent people, 0 artistic and athletic people,  1 person that matches the 3 of the words, and 2 people that doesn’t match any of those. Problems I had was that I didn’t know who was what and also, I forgot who I already counted or not.